Immunohistochemical analysis of Ki-67 antigen and Bcl-2 protein expression in prostate cancer: effect of neoadjuvant hormonal therapy.
OBJECTIVE
To determine differences in the immunohistochemical (IHC) expression of Bcl-2 protein and Ki-67 antigen in patients with prostatic cancer who underwent radical prostatectomy with or without neoadjuvant hormonal therapy.


METHODS
Ki-67 antigen and Bcl-2 protein were detected by IHC using MIB-1 and Bcl-2 antibodies in prostatectomy specimens from 28 patients who received hormonal therapy before surgery (group 1) and 51 patients who did not (group 2).


RESULTS
In group 2, the mean MIB-1 index increased with increasing grade of tumour, from 11.6% in low-grade to 24.7% in high-grade tumours (P = 0.002). Bcl-2 expression did not correlate with either tumour grade or stage. In group 1, there were no correlations between Bcl-2 expression or MIB-1 index and tumour grade or stage. More tumours in group 1 were Bcl-2-positive (16 of 28, 57%) than were tumours in group 2 (11 of 51, 22%; P = 0.003). The mean (SD) MIB-1 index of tumours in group 2 [15.6 (14.4)%], was significantly greater than that of tumours in group 2 [6.8 (7.5)%; P = 0.004].


CONCLUSIONS
These results indicate that Bcl-2 positivity is increased by androgen ablation therapy and conversely, that the proliferative activity of cancer cells is significantly reduced. The expression of Bcl-2 protein may play a role in the ability of prostate cancer cells to survive in an androgen-deprived environment.
Tsuji
M
M
Department of Urology, School of Medicine, University of Tokushima, Japan.
Murakami
Y
Y
Kanayama
H
H
Sano
T
T
Kagawa
S
S
D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000601:surgery; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*
D018931:Antineoplastic Agents, Hormonal; D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2